The nice thing about recycling USB cables for a power supply: just look for the black (-) and red (+) wires when you split the cable open.

While we're at it, we briefly talk about Linear Voltage Regultors (like the 7805) which act like a variable resistors, tend to heat up, and can only reduce voltage vs. Stepping Voltage Regulators, which turn off and on to regulate voltage, are super efficient, generate less heat, and can raise or lower voltage.

Did I say we? David's off building the studio this week, and Brendan's locked in a server closet.